U.S. patent number 9,934,885 [Application Number 13/716,497] was granted by the patent office on 2018-04-03 for electrical harness.
This patent grant is currently assigned to ROLLS-ROYCE plc. The grantee listed for this patent is ROLLS-ROYCE PLC. Invention is credited to Paul Broughton, Robin Charles Kennea.
United States Patent |
9,934,885 |
Broughton , et al. |
April 3, 2018 |
Electrical Harness
Abstract
A gas turbine engine 10 is provided with electrical harness
rafts 200 comprising electrical conductors embedded in a rigid
composite material. The rafts 200 are used to transport electrical
signals (which may be, for example power and/or control signals)
around a gas turbine engine. Rafts 200 may be connected together
and to other components using flexible cables, that may help to
accommodate relative movement of the rafts 200, for example through
vibration. The rafts 200 are lighter, more compact, and more
convenient to handle than conventional electrical harnesses. The
rafts 200 may provide a convenient and secure mounting surface for
other components/systems of a gas turbine engine, such as EECs
and/or fluid pipes.
Inventors: |
Broughton; Paul (Leicester,
GB), Kennea; Robin Charles (Nottingham,
GB) |
Applicant: |
Name |
City |
State |
Country |
Type |
ROLLS-ROYCE PLC |
London |
N/A |
GB |
|
|
Assignee: |
ROLLS-ROYCE plc (London,
GB)
|
Family
ID: |
45572894 |
Appl.
No.: |
13/716,497 |
Filed: |
December 17, 2012 |
Prior Publication Data
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Document
Identifier |
Publication Date |
|
US 20130161093 A1 |
Jun 27, 2013 |
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Foreign Application Priority Data
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Dec 22, 2011 [GB] |
|
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1122140.5 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01B
7/282 (20130101); F02C 7/00 (20130101); H05K
1/18 (20130101); H01B 7/17 (20130101); H05K
1/00 (20130101); F02C 7/32 (20130101); H01B
7/0045 (20130101); H05K 2201/10295 (20130101); H05K
1/144 (20130101); H05K 1/147 (20130101); Y02A
30/14 (20180101); H05K 2201/058 (20130101); Y02T
50/60 (20130101); H01R 12/61 (20130101); H01R
12/78 (20130101) |
Current International
Class: |
H01B
7/00 (20060101); H05K 1/00 (20060101); H05K
1/18 (20060101); H01B 7/17 (20060101); H01B
7/282 (20060101); F02C 7/32 (20060101); F02C
7/00 (20060101); H01R 12/78 (20110101); H01R
12/61 (20110101); H05K 1/14 (20060101) |
References Cited
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Primary Examiner: Patel; Ishwarbhai B
Assistant Examiner: Paghadal; Paresh
Attorney, Agent or Firm: Oliff PLC
Claims
We claim:
1. A gas turbine engine installation comprising an electrical
system arranged to transfer electrical signals around the engine
installation, the electrical system comprising: an electrical
harness raft comprising first multiple insulated electrical
conductors and second multiple electrical conductors, the first
multiple insulated electrical conductors being integrally embedded
in a rigid material so as to be surrounded by and fixed in position
by the rigid material such that the rigid material directly
contacts the first multiple insulated electrical conductors
consistently along the outer surfaces of the entire lengths of the
first multiple insulated electrical conductors, the second multiple
electrical conductors being provided in a flexible printed circuit
that is embedded in the rigid material, the electrical harness raft
forming a first engine installation component; a second engine
installation component comprising electrical conductors; and at
least one flexible cable connected between the electrical harness
raft and the second engine installation component so as to
electrically connect the first multiple insulated electrical
conductors and/or the second multiple electrical conductors of the
electrical harness raft with the electrical conductors of the
second engine installation component, the electrical harness raft
having embedded therein at least one electrical connector, the at
least one electrical connector being in electrical contact with at
least one of the first multiple insulated electrical conductors
embedded in the rigid material and having terminals for connection
with a complimentary connector, the flexible cable comprising the
complimentary connector that is connected to the corresponding
electrical connector embedded in the electrical harness raft.
2. The gas turbine engine installation according to claim 1,
wherein the rigid material is a rigid composite material.
3. The gas turbine engine installation according to claim 1,
wherein the second engine component is a second electrical harness
raft comprising further electrical conductors embedded in a rigid
material.
4. The gas turbine engine installation according to claim 1,
wherein the second engine component is an electronic control
unit.
5. The gas turbine engine installation according to claim 1,
wherein: the gas turbine engine installation comprises a bypass
flow duct formed between an engine core and an engine fan casing;
and the electrical harness raft forms at least a part of a radially
extending splitter that extends across the bypass flow duct.
6. The gas turbine engine installation according to claim 1,
wherein at least one of the first multiple insulated electrical
conductors comprises an electrically conductive wire.
7. The gas turbine engine installation according to claim 1,
wherein the at least one flexible cable comprises at least one of:
a flexible printed circuit having electrically conductive tracks in
a substrate; and an electrically insulated conductive wire.
8. The gas turbine engine installation according to claim 1,
further comprising at least one fluid pipe mounted on the
electrical harness raft and/or at least one electronic control unit
mounted on the electrical harness raft, the electronic control unit
optionally being electrically connected to one or more of the first
multiple insulated electrical conductors and/or the second multiple
electrical conductors in the electrical harness raft on which the
electronic control unit is mounted using second complimentary
electrical connectors provided in the electronic control unit and
the electrical harness raft.
9. The gas turbine engine installation according to claim 1,
further comprising at least one anti-vibration mount through which
the electrical harness raft is attached to the rest of the gas
turbine installation.
10. The gas turbine engine installation according to claim 1,
further comprising a fan casing on which the electrical harness
raft is mounted.
11. The gas turbine engine installation according to claim 10
comprising at least one additional electrical harness raft, wherein
the electrical harness raft and the additional electrical harness
raft are shaped to correspond to a portion of an outer surface of
the fan casing to which they are mounted, such that the fan casing
is at least partially surrounded by the electrical harness raft and
the additional electrical harness raft.
12. The gas turbine engine installation according to claim 1,
wherein the first multiple insulated electrical conductors and the
second multiple electrical conductors are embedded in the rigid
material such that the rigid material surrounds the first multiple
insulated electrical conductors and the second multiple electrical
conductors along an entire length of the first multiple insulated
electrical conductors and the second multiple electrical
conductors.
13. A method of assembling a gas turbine engine installation
comprising: installing an electrical harness raft having first
multiple insulated electrical conductors and second multiple
electrical conductors, the first multiple insulated electrical
conductors being arranged to transfer electrical signals around the
engine and being integrally embedded in a rigid material so as to
be surrounded by and fixed in position by the rigid material such
that the rigid material directly contacts the first multiple
insulated electrical conductors consistently along the outer
surfaces of the entire lengths of the first multiple insulated
electrical conductors, the second multiple electrical conductors
being provided in a flexible printed circuit that is embedded in
the rigid material; and connecting a flexible cable between the
electrical harness raft and another engine installation component
comprising electrical conductors, so as to electrically connect the
first multiple insulated electrical conductors and/or the second
multiple electrical conductors of the electrical harness raft with
the electrical conductors of the other engine installation
component, the electrical harness raft having embedded therein at
least one electrical connector, the at least one electrical
connector being in electrical contact with at least one of the
first multiple insulated electrical conductors embedded in the
rigid material and having terminals for connection with a
complimentary connector, the flexible cable comprising the
complimentary connector that is connected to the corresponding
electrical connector embedded in the electrical harness raft.
14. The method of assembling the gas turbine engine installation
according to claim 13, wherein the first multiple insulated
electrical conductors and the second multiple electrical conductors
are embedded in the rigid material such that the rigid material
surrounds the first multiple insulated electrical conductors and
the second multiple electrical conductors along an entire length of
the first multiple insulated electrical conductors and the second
multiple electrical conductors.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority
from British Patent Application Number GB1122140.5 filed 22 Dec.
2011, the entire contents of which are incorporated by
reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a network for distributing signals and
power around a gas turbine engine using an electrical harness. In
particular, aspects of this invention relate to embedding
electrical conductors into a rigid harness for use in distributing
electricity around a gas turbine engine.
2. Description of the Related Art
A typical gas turbine engine has a substantial number of electrical
components which serve, for example, to sense operating parameters
of the engine and/or to control actuators which operate devices in
the engine. Such devices may, for example, control fuel flow,
variable vanes and air bleed valves. The actuators may themselves
be electrically powered, although some may be pneumatically or
hydraulically powered, but controlled by electrical signals.
Electrical power, and signals to and from the individual electrical
components, are commonly transmitted along conductors.
Conventionally, such conductors may be in the form of wires and/or
cables which are assembled together in a harness. In such a
conventional harness, each wire may be surrounded by an insulating
sleeve, which may be braided or have a braided cover. The
connections between the individual components and the conventional
harness are made, for example, by multi-pin plug and socket
connectors. Similarly, communication between the harness and power,
control and signalling circuitry is achieved through a multi-pin
connector.
By way of example, FIG. 1 of the accompanying drawings shows a
typical gas turbine engine including two conventional wiring
harnesses 102, 104, each provided with a respective connector
component 106, 108 for connection to circuitry, which may be for
example accommodated within the airframe of an aircraft in which
the engine is installed.
The harnesses 102, 104 are assembled from individual wires and
cables which are held together over at least part of their lengths
by suitable sleeving and/or braiding. Individual wires and cables,
for example those indicated at 110, emerge from the sleeving or
braiding to terminate at plug or socket connector components 112
for cooperation with complementary socket or plug connector
components 114 on, or connected to, the respective electrical
components.
Each conventional harness 102, 104 therefore comprises a multitude
of insulated wires and cables. This makes the conventional harness
bulky, heavy and difficult to manipulate. The conventional
harnesses occupy significant space within a gas turbine engine (for
example within the nacelle of a gas turbine engine), and thus may
compromise the design of the aircraft, for example the size and/or
weight and/or shape of the nacelle.
Conventional harnesses comprise a large number of components,
including various individual wires and/or bundles of wires,
supporting components (such as brackets or cables) and electrical
and/or mechanical connectors. This can make the assembly process
complicated (and thus susceptible to errors) and/or time consuming.
Disassembly of the conventional harnesses (for example removal of
the conventional harnesses from a gas turbine engine during
maintenance) may also be complicated and/or time consuming. Thus,
in many maintenance (or repair or overhaul) procedures on a gas
turbine engine, removal and subsequent refitting of the
conventional electrical harness may account for a very significant
portion of the operation time and/or account for a significant
proportion of the potential assembly errors.
The electrical conductors in the conventional harnesses may be
susceptible to mechanical damage. For example, mechanical damage
may occur during installation (for example through accidental
piercing of the protective sleeves/braiding) and/or during service
(for example due to vibration). In order to reduce the likelihood
of damage to the conductors in a conventional harness, the
protective sleeves/braiding may need to be further reinforced,
adding still further weight and reducing the ease with which they
can be manipulated.
OBJECTS AND SUMMARY OF THE INVENTION
According to the present invention, there is provided a gas turbine
engine installation comprising an electrical system (which may be
referred to in general as an electrical harness) arranged to
transfer electrical signals around the engine installation. The
electrical system (or harness) comprises an electrical harness
raft, which comprises electrical conductors embedded in a rigid
material.
According to an aspect of the invention, the gas turbine
installation comprises such an electrical harness raft comprising
multiple (or more than one) electrical conductors embedded in a
rigid material. The electrical harness raft may be at least a part
of a first engine installation component. The gas turbine engine
installation also comprises a second engine installation component
which comprises electrical conductors. At least one flexible cable
is connected between the electrical harness raft and the second
engine installation component so as to electrically connect
electrical conductors of the electrical harness raft with
electrical conductors of the second engine installation
component.
According to a further aspect of the invention, there is provided a
method of assembling a gas turbine engine installation. The method
comprises installing an electrical harness raft having multiple
electrical conductors arranged to transfer electrical signals
around the engine embedded in a rigid material. The method
comprises connecting a flexible cable between the electrical
harness raft and another (second) engine installation component
comprising electrical conductors so as to electrically connect
electrical conductors of the electrical harness raft with
electrical conductors of the other engine installation
component.
Aspects of the invention described herein may apply to the method
of assembly of a gas turbine engine (or gas turbine engine
installation) as well as to the apparatus (for example the gas
turbine engine installation).
The gas turbine engine installation (which may simply be a gas
turbine engine) may comprise any number of electrical harness
rafts. Any one or more rafts may be connected together and/or to
other components using flexible cables. For example, one electrical
harness raft may be directly electrically connected (for example
using a flexible cable) to one, two, three, four, five, six, seven,
eight, nine, ten or more than ten other components, such as other
electrical harness rafts.
It will be appreciated that the electrical signals transferred
around the engine using the electrical harness rafts may take any
form. For example, the electrical signals may include, by way of
non-limitative example, electrical power and/or electrical
control/communication signals and/or any other type of transmission
through an electrical conductor. Transmission of signals around the
engine may mean transmission of signals between (to and/or from)
any number of components/systems in the engine and/or
components/system of a structure (such as an airframe) to which the
gas turbine engine is (or is configured to be) connected/installed
in. In other words, an electrical harness raft may be used to
transfer/communicate any possible combination of electrical signals
in any part of a gas turbine engine installation or a related (for
example electrically and/or mechanically connected)
structure/component/system.
The electrical conductors embedded in the rigid material may be
used to transfer electrical signals around a gas turbine engine.
Embedding electrical conductors in a rigid material (to create an
electrical harness raft) has a great number of advantages over
transferring electrical signals using a conventional harness, at
least some of which are discussed herein.
The electrical harness rafts may provide greater protection to the
electrical conductors than a conventional harness. For example, the
rigid and/or hard material (which may be a rigid and/or hard
composite material) in which the conductors are embedded may
provide greater protection (for example greater mechanical
protection) to the embedded conductors, for example due to being
resistant to breaking and/or snapping and/or piercing and/or
puncturing. Purely by way of example, the use of electrical harness
rafts may reduce, or substantially eliminate, the chance of foreign
bodies coming into contact with the electrical conductors, for
example through fluid ingress. The electrical harness raft(s) may
provide improved protection to the electrical conductors during
manufacture/assembly of the raft/gas turbine installation, and/or
during service/operation/maintenance of the gas turbine engine.
This may result in lower maintenance costs, for example due to
fewer damaged components requiring replacement/repair and/or due to
the possibility of extending time intervals (or service intervals)
between inspecting the electrical system, for example compared with
a system using only conventional harnesses.
Use of one or more electrical harness rafts may significantly
reduce build time of an engine. For example, use of electrical
harness rafts may significantly reduce the part count involved in
engine assembly compared with a conventional harness arrangement.
The number and/or complexity of the operations required to assemble
an engine (for example to assemble/install the electrical system
(or network) and/or other peripheral components, which may be
referred to in general as engine dressing) may be reduced. For
example, rather than having to install/assemble a great number of
wires and/or wiring looms together on the engine installation, it
may only be necessary to attach a relatively small number of
electrical harness rafts, which themselves may be straightforward
to handle, position, secure and connect. Connection between the
rafts and other electrical components using the flexible cable(s)
may be particularly convenient and straightforward. Thus, use of
electrical harness rafts in a gas turbine installation may reduce
assembly time and/or reduce the possibility of errors occurring
during assembly.
Use of electrical harness rafts may provide significant advantages
during maintenance, such as repair and overhaul. As discussed
above, the electrical harness rafts may be particularly quick and
straightforward to assemble. The same advantages discussed above in
relation to assembly apply to disassembly/removal from the gas
turbine engine. Thus, any repair/overhaul that requires removal of
at least a part of the electrical harness may be simplified and/or
speeded up through use of electrical harness rafts, for example
compared with conventional harnesses. Use of electrical harness
rafts may allow maintenance procedures to be advantageously
adapted. For example, some maintenance procedures may only require
access to a certain portion of the gas turbine engine that only
requires a part of the harness to be removed. It may be difficult
and/or time consuming, or not even possible, to only remove the
required part of a conventional harness from a gas turbine engine.
However, it may be relatively straightforward to only remove the
relevant electrical harness raft, for example by simply
disconnecting it from the engine and any other electrical harness
rafts/components to which it is connected. Decreasing maintenance
times has the advantage of, for example, reducing out-of service
times (for example off-wing times for engines that are used on
aircraft).
The build/assembly times may be additionally or alternatively
reduced by pre-assembling and/or pre-testing individual and/or
combinations of electrical harness rafts prior to engine assembly.
This may allow the electrical and/or mechanical operation of the
electrical harness rafts to be proven before installation, thereby
reducing/eliminating the testing required during engine
installation.
The electrical harness rafts may be a particularly lightweight
solution for transferring electrical signals around an engine. For
example, an electrical harness raft may be lighter, for example
significantly lighter, than a conventional harness required to
transmit a given number of electrical signals. A plurality of
conductors may be embedded in a single electrical harness raft,
whereas in a conventional arrangement a large number of heavy,
bulky wires and/or insulating sleeves would be required. The
reduced weight may be particularly advantageous, for example, when
used on gas turbine engines on aircraft.
Electrical harness rafts may be more easily packaged and/or more
compact, for example than conventional harnesses. Indeed, the
electrical harness rafts can be made into a very wide range of
shapes as desired. This may be achieved, for example, by
manufacturing the electrical harness rafts using a mould conforming
to the desired shape. As such, each electrical harness raft may be
shaped, for example, to turn through a tighter corner (or smaller
bend radius) than a conventional harness. The electrical harness
rafts may thus provide a particularly compact solution for
transferring electrical signals around a gas turbine engine. The
electrical harness rafts may be readily shaped to conform to
neighbouring components/regions of a gas turbine engine, for
example components/regions to which the particular electrical
harness raft is attached.
The environment of a gas turbine engine during operation may be
particularly severe, with, for example, high levels of vibration
and/or differential expansion between components as the temperature
changes through operation and as the components move relative to
each other. Providing at least one flexible cable to connect an
electrical harness raft to another component may allow the
electrical harness rafts and/or components to accommodate vibration
and/or relative movement, for example of the
component(s)/assemblies to which they are attached/mounted during
use. For example, the flexible cable(s) used to electrically
connect electrical harness raft(s) to other component(s) may have
sufficient length to accommodate such vibration and/or movement
during use.
For example, providing separate (for example more than one)
electrical harness rafts and connecting at least some (for example
at least two) of them together using at least one flexible cable
may allow the electrical harness rafts to accommodate vibration
and/or relative movement of the component(s)/assemblies to which
they are attached/mounted during use.
The rigid material may be any suitable material, such as a rigid
composite material. The rigid composite material may comprise any
suitable combination of resin and fibre as desired for a particular
application. For example, any of the resins and/or fibres described
herein may be used to produce a rigid composite material for the
electrical harness raft.
The second engine installation component may be any suitable
component, for example a further electrical harness raft comprising
(multiple) electrical conductors embedded in a rigid material.
Thus, more than one electrical harness raft may be provided in the
engine installation. At least two electrical harness rafts may be
electrically connected together using a flexible cable.
The second engine component may be an electronic control unit.
Examples of electronic control units (ECUs) that could form at
least a part of the second engine component include Electronic
Engine Controllers (EECs) and Engine Health Monitoring Units
(EMUs). Thus electrical conductors in the ECUs may be connected to
electrical conductors of the electrical harness raft, for example
via the flexible connecting cable.
The electrical harness raft may be provided in any suitable
location/position of the gas turbine engine installation. For
example, the gas turbine engine may comprise a bypass flow duct
formed between an engine core and an engine fan casing (the gas
turbine engine may be a turbofan engine, for example); and the
electrical harness raft may form at least a part of a radially
extending splitter (which may be referred to as a bifurcation) that
extends across the bypass flow duct. In this way, an electrical
harness raft (which may be referred to as a splitter electrical
harness raft) may provide an electrical connection between a fan
casing and an engine core.
The splitter electrical harness raft may be electrically connected
to other components (for example to one or more other electrical
harness rafts) using the flexible cable. Alternatively or
additionally, a splitter electrical harness raft may be
electrically connected to one or more other electrical harness
rafts directly, for example using connectors embedded in the
respective rafts.
Any of the features described herein in relation to any electrical
harness raft (including components/systems attached thereto/mounted
thereon) may apply to a splitter electrical harness raft. For
example, the splitter electrical harness raft may be provided with
appropriate connectors, which may be used to connect to a
corresponding connector, for example provided on the flexible
connecting cable and/or on other components to which the splitter
electrical harness raft may be provided. By way of further example,
the splitter electrical harness raft may be provided with (for
example have mounted thereon) components and/or other systems, such
as pipes of fluid systems. Such systems/components may need to pass
between the engine core and the fan case, for example fluid
systems, such as fuel/oil/hydraulic/pneumatic/cooling air/sealing
air systems.
The splitter electrical harness raft may be located, or embedded,
inside a surrounding splitter (or bifurcation) structure. Other
components may also be mounted inside such a surrounding splitter
structure, for example a drive shaft in the case that the case
turbine engine has a fan mounted accessory gearbox to which
power/drive must be supplied.
At least some of the advantages of using the electrical harness
rafts (for example as described herein) may be particularly
applicable to a splitter electrical harness raft.
For example, at least a part of the splitter electrical harness
raft crosses the bypass flow between the engine core and the fan
case. Thus, any external surfaces (which may be formed by the
splitter electrical harness raft itself or by a surrounding
splitter structure) are of particular importance because they are
gas-washed by the propulsive bypass flow. Because the electrical
harness raft is much smaller than a conventional harness for a
given number of electrical conductors, the size of the splitter may
be reduced, and thus the detrimental impact on the bypass flow may
be reduced, thereby improving (i.e. reducing) specific fuel
consumption.
In order for electrical conductors to change from travelling around
the fan case to go through a splitter, they need to change
direction through approximately 90 degrees (for example to go from
a circumferential/axial direction to a radial direction). As
mentioned herein, conventional electrical harness are bulky and
have large minimum bend radii. Thus, a significant amount of space
(and material, which contributes to weight) is required in order to
effect such a direction change. However, use of a splitter
electrical harness raft alleviates/eliminates this problem, because
the large bend radii are not required. For example, the splitter
raft itself could be manufactured to have a low radius, compact,
direction change at one (or both ends), such that the electrical
connectors embedded therein become substantially aligned with those
of another raft (which may, for example, run circumferentially
around the engine). Alternatively or additionally, the splitter
raft (and/or raft to which it is to be connected) may have
connectors embedded therein at an angle suitable to accommodate a
direction change of the electrical conductors.
A further advantage of using a splitter electrical harness raft is
that it may facilitate separation of the engine core from the
engine fan case. In order to achieve such separation, the splitter
electrical harness raft may simply need to be detached from its
connections with other components (such as other rafts) and
removed. This may be a lot more straightforward than disconnecting
and detaching the multitude of conductors/wires of a conventional
harness.
At least one of the electrical conductors embedded in the
electrical harness raft may be an electrically conductive wire. The
or each electrically conductive wire may be surrounded by an
electrically insulating sleeve. As such, individual wires may be
laid into (or embedded in) the electrical harness raft, and each
wire may be used to transfer one or more electrical signals through
the raft and around the engine. Providing a sleeve to the
individual wires may provide extra mechanical and/or electrical
protection/isolation.
At least some (for example a plurality) of the electrical
conductors may be provided in a flexible printed circuit. Thus, at
least some of the electrical conductors may be provided as
electrically conductive tracks in a flexible substrate. The
flexible printed circuit may be flexible before being embedded in
the rigid material.
Providing the electrical conductors as tracks in a flexible printed
circuit may allow the size of the resulting electrical harness raft
to be reduced further and/or substantially minimized. For example,
many different electrical conductors may be laid into a flexible
printed circuit in close proximity, thereby providing a compact
structure. The flexible substrate of a single flexible printed
circuit may provide electrical and/or mechanical
protection/isolation to a large number of electrical
conductors.
Any given electrical harness raft may be provided with one or more
electrical wires embedded therein (which may be sheathed) and/or
one or more flexible printed circuits embedded therein. As such, a
given electrical harness raft may have wires and flexible printed
circuits laid therein.
It will be appreciated that the embedded electrical conductors
(whether they are provided as embedded electrical wires or as
conductive tracks in a flexible printed circuit embedded in the
rigid material) may be described as being fixed in position by the
rigid material, for example relative to the rest of the electrical
harness raft. It will also be appreciated that the embedded
electrical conductors may be said to be surrounded by the rigid
material and/or buried in the rigid material and/or integral with
(or integrated into) the rigid material.
The or each flexible cable (connected between the first electrical
harness raft and the second engine installation component) may
comprise a flexible printed circuit having electrically conductive
tracks in a substrate. The or each flexible cable (connected
between the first electrical harness raft and the second electrical
harness raft) may comprise an electrically insulated conductive
wire. Any combination of wires and flexible printed circuits may be
used to electrically connect two electrical harness rafts
together.
At least one electrical harness raft may have embedded therein (or
may be provided with) at least one electrical connector (or
socket). The or each electrical connector may be in electrical
contact with at least one of the respective electrical conductors
embedded in the rigid material and may have terminals for
connection with a complimentary connector.
Providing electrical harnesses with integral electrical
sockets/electrical connectors (for example by embedding them in the
raft, for example to secure them in place relative to the raft) may
provide a particularly quick, efficient and reliable means to
connect (for example electrically connect) components to the
electrical harness rafts and/or to connect electrical harness rafts
together (either directly or indirectly).
The or each flexible cable (connected between the first electrical
harness raft and the second electrical harness raft) may comprise
complimentary connectors that are connected to corresponding
electrical connectors embedded in the electrical harness raft(s).
In this way, assembly of the electrical harness raft to other
components (including to each other) may be facilitated. For
example, it may be possible to connect an electrical harness raft
to another component (such as another electrical harness raft)
simply by connecting one set of (or in some cases more than one set
of, such as two, three, four, five or more than five) complimentary
connectors/sockets together at each raft.
Some electrical harness rafts may be provided with electrical
connectors that are complimentary to electrical connectors provided
with other components, such as other electrical harness rafts. This
may allow some electrical harness rafts to be electrically
connected to other components directly, using the complimentary
sockets embedded therein, rather than (or in addition to) using
flexible cables. This may be appropriate in regions of the engine
in which it is not necessary to have a flexible cable connecting
two rafts together.
One or more electrical harness raft may be mechanically and/or
electrically connected to other components/systems of the gas
turbine engine, for example ancillary, auxiliary or control
components. Such other components/systems may be provided to an
electrical harness raft in any suitable manner. For example, such
other components/systems may be mounted on one or more electrical
harness rafts. Thus, a surface of an electrical harness may be used
as a mounting surface for other gas turbine engine
components/systems, such as ancillary/auxiliary
components/systems.
At least one electrical harness raft may have an electronic control
unit (ECU) mounted thereon. Such an electronic control unit may be
an electronic engine controller (EEC). The electrical harness raft
may provide a convenient surface on which to mechanically mount
such an ECU/EEC. The electrical harness raft may be provided with
(for example have embedded therein) an electrical connector/socket
that can be connected to a corresponding (or complimentary)
connector on an ECU/EEC which may be physically mounted on the
raft. Thus, the electrical harness raft may provide a convenient,
compact, and lightweight solution for mounting and/or connecting
ECUs/EECs to the engine, and/or for electrically connecting the
EEC/ECU to one or more of the electrical conductors in the
electrical harness raft on which it is mounted
Thus, through the use of suitable complimentary (or corresponding)
connectors provided to the ECU (or EEC) and the corresponding
electrical harness raft, the ECU/EEC may be electrically connected
to one or more of the electrical conductors in the electrical
harness raft on which it is mounted in a particularly convenient,
compact, and lightweight manner.
At least one electrical harness raft may be provided with at least
one mount on which components (for example auxiliary/ancillary
components/systems) of the gas turbine engine are (or may be)
mounted. The mount may be a bracket, for example a bespoke bracket
for the component/system mounted thereon or a conventional/standard
bracket. The electrical harness raft may provide a stable, regular
and convenient platform on which to mount the various
systems/components. The combination of the installed electrical
harness raft with components/systems mounted thereon may be much
more compact and/or straightforward to assemble and/or have a
greatly reduced number of component parts, for example compared
with the corresponding conventional electrical harness and
separately mounted components/systems.
The mounts may be used to attach any component/system to an
electrical harness raft (and thus to the engine) as required. For
example, fluid pipes for transferring fluid around the engine may
be mounted to the electrical harness rafts (for example
mechanically mounted using a bracket), and thus to the engine. The
fluid pipes may be arranged to carry any fluid as desired,
including gas (such as cooling air, sealing air, and/or muscle air
(for example for pneumatic systems)) and/or liquid (such as fuel,
water, oil and/or hydraulic fluid). Of course, more than one set of
fluid pipes, for example for carrying different or the same fluids,
may be mounted on the same electrical harness raft.
Examples of other components/systems that may be at least in part
mounted to an electrical harness raft include, by way of
non-limitative example: fire detectors and/or fire detection
elements; thermocouples for measuring air temperature (for example
within a particular engine zone); vibration monitoring processing
equipment (for example a signal processing component/box containing
electronics used to process a vibration signal that may be measured
elsewhere in the engine); equipment for measuring fluid quality
(for example a probe for oil debris monitoring may be provided to
one or more pipes mounted to the raft, and/or a signal processing
box for processing the oil quality measurements may be mounted on
the box); and pressure sensors and/or signal processing equipment,
for example for fluid pipes mounted on the rafts.
An engine installation according to the present invention may
comprise raft assemblies that do not have electrical conductors
embedded therein. Such raft assemblies may provide one or more
mounting surfaces for engine components/systems, such as (by way of
non-limitative example) any one or more of the components/systems
disclosed herein as being optionally mounted on an electrical
harness raft. For example, an embodiment may have at least one
electrical harness raft, together with at least one raft assembly
that does not have electrical conductors embedded therein.
Components/systems may be mounted to and/or extend between an
electrical harness raft and a raft assembly that does not have
electrical conductors embedded therein.
At least one electrical harness raft (for example some or all of
the electrical harness rafts where more than one electrical harness
raft is provided) may be connected/attached/mounted to the gas
turbine engine using at least one anti-vibration mount. Using an
anti-vibration mount to attach the electrical harness raft to the
gas turbine engine may reduce (or substantially eliminate) the
amount (for example the amplitude and/or the number/range of
frequencies) of vibration being passed to the electrical harness
raft from the gas turbine engine, for example during use. This may
help to prolong the life of the electrical harness raft.
Furthermore, any other components that may be attached to the
electrical harness raft (as discussed above and elsewhere herein)
may also benefit from being mounted to the gas turbine engine via
the anti-vibration mounts, through being mounted on the electrical
harness raft. This may mean that any components that would
conventionally be mounted directly to the gas turbine engine and
require at least a degree of vibration isolation no longer require
their own dedicated anti-vibration mount. Such components may
include, for example, Electronic Engine Controllers (EECs) and
Engine Health Monitoring Units (EMUs). Thus, the total number of
anti-vibration mounts that are required to assemble an engine may
be reduced. This may reduce the number of parts required and the
time taken to assemble an engine or engine installation and/or
reduce the total assembled weight and/or reduce the likelihood of
errors occurring during assembly.
Furthermore, components that are conventionally mounted to an
engine without anti-vibration mounts (for example because of the
weight and/or cost penalty), but which are now mounted to an
electrical harness raft, may benefit from vibration isolation
without any weight/cost/assembly time penalty. This may reduce the
possibility of damage occurring to such components and/or increase
their service life. Such components may include, for example,
ignitor boxes (used to provide high voltage power to engine
ignitors), and pressure sensors/switches, for example for fluid
systems such as oil, air, fuel, pneumatics and/or hydraulics.
According to an aspect of the invention, there is provided a fan
casing for a gas turbine engine (for example a high bypass ratio
gas turbine engine) provided with an electrical harness raft, which
comprises electrical conductors for transferring electrical signals
around a gas turbine engine embedded in a rigid material. One or
more electrical harness rafts may be attached to the fan casing
(for example using anti-vibration mounts, as described above and
elsewhere herein). Electrical harness rafts may be connected
together and/or to other components of the gas turbine engine using
at least one flexible cable to electrically connect electrical
conductors of the components together. The electrical harness
raft(s) and/or the connecting flexible cables may comprise or be
provided with any of the features described herein, for example in
relation to a gas turbine engine installation.
One or more of the electrical harness rafts may be shaped to
correspond to a portion of an outer surface of the fan casing to
which they are mounted. In this case, the fan casing may be said to
be at least partially surrounded by electrical harness rafts.
Conforming the electrical harness rafts to the shape of the fan
casing (for example to the shape of the outer surface of the fan
casing) may be a particularly compact solution for providing
electrical signals around the gas turbine engine, for example
around at least a part of the circumference of the gas turbine
engine.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described, by way of example only, with
reference to the accompanying Figures, in which:
FIG. 1 shows a gas turbine engine with a conventional harness;
FIG. 2 shows a cross-section through a gas turbine engine having an
electrical harness raft in accordance with the present
invention;
FIG. 3 shows a schematic of an electrical harness raft prior to
assembly;
FIG. 4 shows a schematic of a cross-section through an electrical
harness raft prior to assembly;
FIG. 5 shows a schematic of a cross-section through the electrical
harness raft of FIG. 4 after assembly;
FIG. 6 shows a schematic of a cross-section through an electrical
harness raft prior to assembly;
FIG. 7 shows a schematic of a cross-section through the electrical
harness raft of FIG. 6 after assembly;
FIG. 8 shows a perspective view of a flexible printed circuit;
FIG. 9 shows a side view of the flexible printed circuit of FIG.
8;
FIG. 10 shows a top view of the flexible printed circuit of FIG.
8;
FIG. 11 shows a cross-sectional view of the flexible printed
circuit of FIG. 8;
FIG. 12 shows a cross-section through a gas turbine engine
according to an embodiment of the invention;
FIG. 13 shows a cross-section through a gas turbine engine
according to an embodiment of the invention;
FIG. 14 shows a cross-section through a gas turbine engine
according to an embodiment of the invention;
FIG. 15 shows a schematic of a splitter assembly having an
electrical harness raft according to the invention;
FIG. 16 shows a cross-section through a splitter assembly having an
electrical harness raft according to the invention; and
FIG. 17 shows a schematic of a cross-section through an electrical
harness raft having first multiple insulated electrical conductors
and second multiple electrical conductors provided in the form of a
flexible printed circuit.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to FIG. 2, a ducted fan gas turbine engine generally
indicated at 10 has a principal and rotational axis X-X. The engine
10 comprises, in axial flow series, an air intake 11, a propulsive
fan 12, an intermediate pressure compressor 13, a high-pressure
compressor 14, combustion equipment 15, a high-pressure turbine 16,
and intermediate pressure turbine 17, a low-pressure turbine 18 and
a core engine exhaust nozzle 19. The engine also has a bypass duct
22 and a bypass exhaust nozzle 23.
The gas turbine engine 10 works in a conventional manner so that
air entering the intake 11 is accelerated by the fan 12 to produce
two air flows: a first air flow A into the intermediate pressure
compressor 13 and a second air flow B which passes through the
bypass duct 22 to provide propulsive thrust. The intermediate
pressure compressor 13 compresses the air flow A directed into it
before delivering that air to the high pressure compressor 14 where
further compression takes place.
The compressed air exhausted from the high-pressure compressor 14
is directed into the combustion equipment 15 where it is mixed with
fuel and the mixture combusted. The resultant hot combustion
products then expand through, and thereby drive the high,
intermediate and low-pressure turbines 16, 17, 18 before being
exhausted through the nozzle 19 to provide additional propulsive
thrust. The high, intermediate and low-pressure turbines 16, 17, 18
respectively drive the high and intermediate pressure compressors
14, 13 and the fan 12 by suitable interconnecting shafts.
The gas turbine engine 10 shown in FIG. 2 may be at least a part of
a gas turbine engine or gas turbine engine installation according
to the present invention. The gas turbine engine 10 comprises at
least one electrical harness raft 200 for transmitting/transferring
electrical signals (or electricity, including electrical power
and/or electrical control signals) around the engine and/or to/from
the engine 10 from other components, such as components of an
airframe. The function and/or construction of the electrical
harness raft 200, and the electrical/mechanical connections between
different electrical harness rafts 200, and between electrical
harness rafts 200 and other components/systems, may be as described
above and elsewhere herein.
In FIG. 2, the electrical harness raft 200 (which may be referred
to herein simply as a raft 200) comprises at least one electrical
conductor 210 embedded in a rigid composite material 220. In the
FIG. 2 embodiment, the electrical harness raft 200 is provided with
a further gas turbine system in the form of fluid pipes or conduits
300 (which may, for example carry liquid and/or gas). The fluid
pipes 300 are attached to the raft 200 using mounting brackets 310.
Alternatively or additionally, the electrical harness raft(s) 200
may be provided with (for example by having mounted thereon or
thereto) other systems and/or components relating to the gas
turbine engine 10. Some rafts 200, on the other hand, may not have
any additional components and/or systems mounted thereon.
The raft 200 (and any components/systems 300 with which it is
provided) is connected to (for example mounted on) the gas turbine
engine 10 using a mount 400. In FIG. 2, the raft 200 is connected
to a fan casing 24 of the gas turbine engine 10 using the mount
400. The raft 200 may thus be radially outward of the fan casing
24, between the fan casing 24 and the outer surface (or nacelle) of
the assembled engine 10. The raft 200 (or other rafts 200) may,
however, be connected to other parts of the gas turbine engine 10.
The mount 400 may be any suitable mount. By way of example, the
mount 400 may be an anti-vibration (or AV) mount configured to
reduce or substantially eliminate vibration from components of the
gas turbine engine 10 being passed to the raft 200, and thus to any
components/systems 300 mounted thereon/connected thereto.
The electrical harness rafts 200 comprise electrical conductors 210
provided in a rigid material. Any rigid material may be suitable,
such as a rigid composite material 220. It will be appreciated that
any suitable method may be used to construct the electrical harness
raft(s) 200.
FIG. 3 shows components of an example of an electrical harness raft
200 prior to one method of construction. The electrical conductors
210 are provided between two layers of material 230, 240 that,
after construction, form the rigid material 220. The material 230,
240 may be a fibre and resin compound. Such a fibre and resin
compound may, after suitable treatment (for example heat treatment)
produce a rigid composite material 220, for example an organic
matrix composite material 220. In the example of FIG. 3, the fibre
and resin compound is formed of a sheet of interwoven fibres, or
strands. The strands in FIG. 3 extend in perpendicular directions,
although the strands may extend in any one or more directions as
required. The strands/fibres may be pre-impregnated (or
"pre-pregged") with the resin.
Any suitable fibres may be used, for example carbon fibres, glass
fibres, aramid fibres, and/or para-aramid fibres. The fibres may be
of any type, such as woven and/or chopped. Any suitable resin may
be used, for example epoxy, BMI (bismaleimide), PEEK
(polyetheretherketone), PTFE (polytetraflouroethylene), PAEK
(polyaryletherketone), polyurethane, and/or polyamides (such as
nylon).
Any suitable material may be used for the rigid material 220. For
example, the rigid material 220 need not be a fibre/resin, or a
composite, material. For example, the electrical conductors 210 may
be embedded in any one or more of the following materials: epoxy,
BMI (bismaleimide), PEEK (polyetheretherketone), PTFE
(polytetraflouroethylene), PAEK (polyaryletherketone),
polyurethane, and/or polyamides (such as nylon). Thus, fibres may
or may not be included in such materials that may form the rigid
material 220. Where fibres are not included in the rigid material
220, a suitable alternative manufacturing process may be used.
The electrical conductors 210 (which may, as described in more
detail elsewhere herein, be of any form, such as conductive wires,
insulated conductive wires, and/or printed flexible circuits such
as those described herein in relation to FIGS. 8 to 11) may be
placed in any desired arrangement between the first and second
layers 230, 240. Prior to any treatment, both the first and second
layers 230, 240 and the electrical conductors 210 may be flexible,
for example supple, pliable or malleable.
As such, when the layers 230, 240 and the electrical conductors 210
are placed together, they may be moulded, or formed, into any
desired shape. For example, the layers 230, 240 and the electrical
conductors 210 may be placed into a mould (which may be of any
suitable form, such as a glass or an aluminium mould) having the
desired shape. The desired shape may be, for example, a shape that
corresponds to (for example is offset from) a part of a gas turbine
engine, such as, by way of example only, at least a part of a
casing, such as an engine fan casing or engine core casing. This
may enable the final raft to adopt shapes that are curved in
two-dimensions or three-dimensions.
In order to produce the rigid raft 200 from the material layers
230, 240 and the electrical conductors 210, the assembly (which may
be in a suitably shaped mould, as described above) may be subject
to a suitable hardening, stiffening, and/or setting treatment. Such
a treatment may involve raising the temperature (i.e. heat
treatment) and/or applying increased pressure. The treatment may be
conducted in, for example, an autoclave. In this way, the
electrical conductors 210 may be said to be sandwiched between the
upper and lower material layers 230, 240.
Any suitable method could be used to produce the rigid raft 200.
For example, the strands/fibres need not be pre-impregnated with
the resin. Instead, the fibres/strands could be put into position
(for example relative to the electrical conductors) in a dry state,
and then the resin could be fed (or pumped) into the mould. Such a
process may be referred to as a resin transfer method.
After the treatment, the rigid electrical harness raft 200 may be
set in the desired shape. Suitable electrical connectors and/or
sockets may be fitted to the raft 200. Such connectors may be
fitted prior to stiffening treatment of the material layers 230,
240 and the electrical conductors 210, or after such treatment. The
connectors may be in electrical connection with the conductors 210
and may have pins or connectors for connection (electrical and/or
mechanical) to other components of the gas turbine engine 10
(including the flexible connection cables and other electrical
harness rafts), as discussed in greater detail elsewhere
herein.
FIG. 4 shows an example of a cross-section through upper and lower
material layers 230, 240 and electrical conductors 210 prior to
being placed together (by moving the upper layer 230 in the
direction of arrow A and the lower layer 240 in the direction of
arrow B) and treated to produce the electrical harness raft 200.
The upper and lower layers 230, 240 in the example shown in FIG. 4
(and FIG. 6, discussed below) may comprise at least one layer, for
example multiple layers, of fibre and/or fibre and resin
compound.
FIG. 5 shows a cross-section through the electrical harness raft
200 produced by the FIG. 4 arrangement, for example after
stiffening treatment. The FIG. 5 raft 200 has five individual
electrical conductors 210, but the electrical harness raft 200
could have any number of electrical conductors 210 embedded
therein, for example fewer than 5, at least 5, at least 10, at
least 50, at least 100.
FIG. 6 shows an example of a cross-section through an alternative
arrangement of conductors between the upper and lower material
layers 230, 240 prior to being placed together, moulded, and
stiffened to produce an electrical harness raft 200. FIG. 7 shows a
cross-section through the electrical harness raft 200 produced by
the FIG. 6 arrangement, for example after stiffening treatment.
In the FIGS. 6 and 7 arrangement, the electrical conductors 210
take a variety of different forms and/or are provided in a variety
of different ways. The conductor 210 on the left hand side of FIGS.
6 and 7 is provided with a sheath, or coating, or sleeve 212. The
sleeve 212 may provide protection to the conductor 210 and/or
electrical insulation. The conductor 210 second from the left in
FIGS. 6 and 7 is unprotected. Thus, the conductor 210 second from
the left in FIGS. 6 and 7 may be, for example, a conductive (for
example metal, for example copper) wire laid directly into the
rigid composite material 220.
The other conductors 210 in the example shown in FIGS. 6 and 7 may
be provided as part of (or in) a flexible printed circuit (FPC)
250, which may be referred to as a flexible printed circuit board
(or FPCB) 250. The FPC 250 comprises conductors 210, which may be
in the form of conductive tracks, laid into a flexible substrate
255. The flexible printed circuit 250 itself may be flexible. It
will be appreciated that the electrical harness raft 200 may
comprise any number of any one or more of the sleeved 212 or
un-sleeved conductors 210 or flexible printed circuits 250.
As discussed in greater detail below, for example in relation to
FIGS. 12, 13, and 14, flexible printed circuits may additionally or
alternatively be used to connect two or more electrical harness
rafts 200 together. The basic structure of flexible printed
circuits 250 used to connect rafts 200 together and to be embedded
in the rafts 200 themselves may be substantially the same, as
discussed below in relation to FIGS. 8 to 11. Thus, the description
of a flexible printed circuit (or flexible printed circuit board)
250 below in relation to FIGS. 8 to 11 may apply to flexible
printed circuits used as flexible cables to connect rafts 200
together, or to flexible printed circuits laid into the rafts
200.
FIG. 8 shows a perspective view of a portion of a flexible printed
circuit (FPC) 250, and FIGS. 9, 10, and 11 show side, top, and
cross-sectional views respectively.
Such an FPC 250 may comprise a flexible (for example elastically
deformable) substrate 255 with conductive tracks 252 laid/formed
therein. The FPC 250 may thus be deformable. The FPC may be
described as a thin, elongate member and/or a sheet-like member.
Such a thin, elongate member may have a major surface defined by a
length and a width, and a thickness normal to the major surface. In
the example shown in FIGS. 8 to 11, the FPC 250 may extend along a
length in the x-direction, a width in the y-direction, and a
thickness (or depth or height) in the z-direction. The x-direction
may be defined as the axial direction of the FPC. Thus, the
x-direction (and thus the z-direction) may change along the length
of the FPC 250 as the FPC is deformed. This is illustrated in FIG.
9. The x-y surface(s) (ie the surfaces formed by the x and y
directions) may be said to be the major surface(s) of the FPC 250.
In the example shown in FIGS. 8 to 11, the FPC is deformable in the
z direction, i.e. in a direction perpendicular to the major
surface. FPCs may be additionally of alternatively deformable about
any other direction, and/or may be twisted about any one or more of
the x, y, or z directions.
The flexible substrate 255 may be a dielectric. The substrate
material may be, by way of example only, polyamide. As will be
readily apparent, other suitable substrate material could
alternatively be used.
The conductive tracks 252, which may be surrounded by the substrate
255, may be formed using any suitable conductive material, such as,
by way of example only, copper, copper alloy, tin-plated copper (or
tin-plated copper alloy), silver-plated copper (or silver-plated
copper alloy), nickel-plated copper (or nickel-plated copper alloy)
although other materials could alternatively be used. The
conductive tracks 252 may be used to conduct/transfer electrical
signals (including electrical power and electrical control signals)
through the electrical harness raft(s) 200, for example around a
gas turbine engine 10 and/or to/from components of a gas turbine
engine and/or an airframe attached to a gas turbine engine.
The conductive tracks 252 shown in FIGS. 8 to 11 may be equivalent
to the conductive tracks 210 shown in the FPC 250 laid in the raft
200 of FIG. 7. Additionally or alternatively, the conductive tracks
252 shown in the FPC of FIGS. 8 to 11 may be used to transfer
electrical signals between electrical harness rafts 200, for
example by using the FPC 250 as a flexible cable to connect two or
more rafts 200 together.
The size (for example the cross-sectional area) and/or the shape of
the conductive tracks 252 may depend on the signal(s) to be
transmitted through the particular conductive track 252. Thus, the
shape and/or size of the individual conductive tracks 252 may or
may not be uniform in a FPC 250.
The example shown in FIGS. 8 to 11 has 6 conductive tracks 252
running through the substrate 255. However, the number of
conductive tracks 252 running through a substrate 255 could be
fewer than 6, or greater than 6. Indeed the number of conductive
tracks 252 could be far greater than 6, for example tens or
hundreds of tracks, as required. As such, many electrical signals
and/or power transmission lines may be incorporated into a single
FPC 250.
A single FPC 250 may comprise one layer of tracks, or more than one
layer of tracks, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more
than 10 layers of tracks. An FPC may comprise significantly more
than 10 layers of tracks, for example at least an order of
magnitude more layers of tracks. In this regard, a layer of tracks
may be defined as being a series of tracks that extend in the same
x-y surface. Thus, the example shown in FIGS. 8 to 11 comprises 2
layers of tracks, with each layer comprising 3 tracks 252.
FIG. 12 is a schematic showing a cross-section perpendicular to the
direction X-X of a gas turbine engine comprising electrical harness
rafts. FIG. 12 shows four electrical harness rafts 200A, 200B,
200C, 200D (which may be referred to collectively as electrical
harness rafts 200). Each electrical harness raft 200A, 200B, 200C,
200D comprises electrical conductors in a rigid material. For
example, each electrical harness raft 200A, 200B, 200C, 200D may be
as described herein, for example as described above in relation to
FIGS. 3-7 in particular. Each electrical harness raft 200A, 200B,
200C, 200D is arranged (for example manufactured) to have a shape
that corresponds to at least a part of the fan casing 24 of the
engine 10 to which it is attached.
Each electrical harness raft 200A, 200B, 200C, 200D is, in the FIG.
12 example, connected to other components using flexible cables
(which may be referred to as "flying leads") 261, 262, 263, 264,
265. The flexible cables 261, 262, 263, 264, 265 may be referred to
as connection cables. The flexible cables 261, 262, 263, 264, 265
may provide electrical connection between the electrical harness
rafts 200A, 200B, 200C, 200D, for example between two or more
electrical harness rafts 200A, 200B, 200C, 200D and/or between
electrical harness raft(s) and other components, for example other
components of a gas turbine engine 10 or other components of a
related structure, such as an airframe.
The flexible cables 261, 262, 263, 264, 265 may take any suitable
form. For example, the flexible cables 261, 262, 263, 264, 265 may
comprise a flexible printed circuit, such as the flexible printed
circuit 250 described above in relation to FIGS. 8 to 11.
Additionally or alternatively, the flexible cables 261, 262, 263,
264, 265 may comprise one or more conductive wires surrounded by an
insulating sleeve. In the same engine installation, and indeed
between two components (such as two electrical harness rafts), some
flexible cables 261, 262, 263, 264, 265 may be flexible printed
circuits, and others may be insulated wires.
The connection, for example the electrical connection, between a
flexible cable 261, 262, 263, 264, 265 and an electrical harness
raft 200 may take any suitable form. For example, an electrical
harness raft 200 may be provided with an electrical connector, or
socket, which is connected to (for example receives or is received
by) a corresponding connector or socket of the respective flexible
cable 261, 262, 263, 264, 265. A schematic example of such an
arrangement is shown in FIG. 12 in relation to the flexible cable
263. The flexible cable 263 has an electrical connector 270A
provided at either end. These electrical connectors 270A are
connected to corresponding electrical connectors 270B in the
electrical harness rafts 200C, 200D being connected together. In
this way, electrical conductors 210 of the electrical harness rafts
200C, 200D may be electrically connected to the flexible cable 263,
and thus to each other. The electrical connectors 270B may be
provided to the electrical harness rafts 2000, 200D in any suitable
manner, for example they may be embedded in the rigid material of
the rafts 200C, 200D. In FIG. 12, only the connection 270A/270B
between the one flexible cable 263 and two rafts 200C, 200D is
shown. However, it will be appreciated that such a connection could
exist between any combination of the flexible cables 261, 262, 263,
264, 265 and/or electrical harness rafts 200 and/or other
components. Alternatively or additionally, and optionally on the
same engine installation, other suitable connection
arrangements/methods could be used to connect (for example
electrically connect) such components together.
The electrical harness rafts 200 may be connected or provided to
the rest of the gas turbine engine 10 in any suitable manner. In
the FIG. 12 example, the electrical harness rafts 200 are connected
to the gas turbine engine 10 using mounts 400 (labelled 400A-400D
in FIG. 12). The mounts 400 could take any suitable form. For
example, the mounts 400 in the FIG. 12 example may be
anti-vibration mounts, so as to reduce/substantially eliminate the
vibration transferred to the respective electrical harness raft
200. In the FIG. 12 example, each raft 200A, 200B, 2000, 200D is
provided with at least two respective mounts 400A, 400B, 4000, 400D
for mounting each raft 200 to the rest of the gas turbine engine
10. However, any suitable number of mounts 400 may be used as
required, for example 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more than 10
mounts 400 per raft.
One or more electrical harness rafts 200 may be provided to (for
example attached to/embedded within) any part/region/component of a
gas turbine engine/gas turbine engine installation 10, for example
using mounts 400. In the FIG. 12 example, electrical harness rafts
200A, 200B, 200C, 200D are connected to a fan casing 24 of the gas
turbine engine 10. As such, the mounts 400A, 400B, 400C, 400D may
be provided between the fan casing 24 and the respective raft 200A,
200B, 200C, 200D.
Purely by way of non-limitative example only, electrical harness
rafts 200 may additionally or alternatively be provided on/attached
to/embedded within the engine core casing 28, the engine core
fairing 26, the bifurcation between the engine core and the engine
fan case (as discussed in relation to FIG. 14), nose cone,
structural frames or elements within the engine (such as
"A-frames"), the nacelle, the fan cowl doors, and/or any connector
or mount between the gas turbine engine 10 and a connected
structure (which may be at least a part of a structure in which the
gas turbine engine 10 is installed), such as the pylon 500 between
the gas turbine engine 10 and an airframe (not shown). For the
avoidance of doubt, the pylon 500, together with other connections
or mounts between the gas turbine engine 10 and a connected
structure (such as an airframe) may be a part of a gas turbine
engine installation.
In the FIG. 12 example, two of the flexible cables 264, 265 are
connected (for example electrically and/or mechanically connected)
to the pylon 500. Thus, the electrical harness rafts 200 may be
connected to an airframe (or aircraft, or other structure/vehicle)
to which the pylon 500 is connected. The pylon 500 itself may have
one or more electrical harness rafts 200 embedded therein and/or
attached thereto. Additionally or alternatively, a component to
which the gas turbine engine/gas turbine engine installation 10 is
attached may be provided with one or more electrical harness
rafts.
FIG. 13 is a schematic cross-section through a gas turbine engine
10 in a plane normal to the engine axis X-X. FIG. 13 is similar
view to the arrangement of FIG. 12. The description of
corresponding features described above in relation to FIG. 12
applies equally to the FIG. 13 example, and will not be repeated in
relation to FIG. 13.
In FIG. 13, at least one of the electrical harness rafts 200 is
used to mount other components/systems of the gas turbine engine
10. In general, any component/system, or a part thereof, of the gas
turbine engine 10 could be mounted on/to (for example
physically/mechanically mounted/connected and/or electrically
connected) one or more of the electrical harness rafts 200. As
discussed herein, as well as providing a particularly compact, easy
to assemble and lightweight mounting solution, mounting
components/systems at least in part on an electrical harness raft
200 may provide vibration isolation/damping, for example if the
mounts 400 used to attach the raft 200 to the rest of the engine 10
is an anti-vibration mount.
Purely by way of non-limitative example, the components/systems
mounted to the rafts 200 in the FIG. 13 example include an
Electronic Engine Controller (or EEC, which may be an Electronic
Control Unit, or ECU) 320 and fluid pipes 300. The EEC 320 may be
used to communicate electronic signals (for example electronic
control signals) with the rest of the engine, for example through
the electronic harness rafts. The fluid pipes 300 may be used to
transport any liquid, gas, or mixture thereof, around the gas
turbine engine installation 10.
The EEC 320 may be electrically connected to the electrical harness
raft 200A on which it is located in any suitable manner. For
example an electrical connector 330A provided to (for example
embedded in) the EEC 320 may be connected to a corresponding, or
complimentary, electrical connector 330B provided to (for example
embedded in) the electrical harness raft 200A. The connector 330B
provided to the electrical raft harness 200A may be in electrical
connection with at least some of the electrical conductors 210
embedded therein. The connector 330A provided to the EEC 320 may be
in electrical connection with electrical or electronic circuits
(for example control circuits) in the EEC 320. Thus, circuits in
the EEC 320 can be in communication with other components through a
electronic raft harness 200, thereby allowing signals (for example
control/communication signals) to be transferred between the EEC
320 and the gas turbine engine installation 10 (and optionally to
other components/parts to which the gas turbine engine installation
is attached). The connectors 330A, 330B may take any suitable
form/shape, such as that described above in relation to the
connectors 270A/270B connecting the flexible cable 263 to the rafts
200C, 200D. The EEC 320 may be mechanically connected to the
electrical harness raft 200A, for example by embedding the EEC 320
into the electrical harness raft 200A and/or by using suitable
mounts/brackets.
As mentioned herein, the fluid pipes/conduits 300 may be used to
transport any fluid around the engine as desired. FIG. 13 shows 3
pipes 300A, 300B, 300C extending in a substantially axial direction
relative to the engine 10. Any number of pipes could be mounted
onto a raft 200, for example 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more
than 10 pipes. Furthermore, pipes 300 could be mounted in any
suitable direction, as desired. For example, in FIG. 2, pipes 300
are shown as extending circumferentially around the engine 10,
whereas in FIG. 13, pipes 300 are shown extending axially along the
engine 10. Each pipe 300 may be mounted in any appropriate manner,
for example using a bracket. A pipe 300 on one raft 200 may be
connected, for example fluidly connected, to a pipe 300 mounted on
a different raft 200. Such a connection may be implemented using
any suitable connector, such as a fluid-tight connector which may
have portion(s) adapted to connected with complimentary portions on
one, two, or more than two pipes 300.
As mentioned elsewhere herein, any suitable component/system or
part thereof could be mounted on an electrical harness raft 200.
Components mounted on electrical harness rafts 200 may be connected
to each other, for example a component mounted on one raft 200 may
be connected (for example directly electrically, mechanically
and/or fluidly connected) to one or more components mounted on
another raft 200. By way of non-limitative example only, an
electrical harness raft 200 could be used to mount electrical
cables, for example to carry electrical signals that are not
carried using the conductors 210 in the electrical harness rafts
200.
In the FIG. 13 example, electrical harness rafts 200E, 200F are
provided on the core casing 28. Thus, electrical harness rafts
200E, 200F are provided between the engine core casing 28 and the
engine core fairing 26. Electrical signals may be passed from the
electrical harness rafts 200A, 200B, 200C, 200D mounted on the fan
casing 24 to the electrical harness rafts 200E, 200F mounted on the
core casing 28. In the FIG. 13 example, this may be achieved by
passing the electrical signals through a bifurcation or splitter
340 in the bypass duct 22, which may be formed at least in part by
an outlet guide vane spanning the bypass duct 22. The bifurcation
340 may comprise, for example have embedded therein or be at least
partially formed by, an electrical harness raft, such as any of the
electrical harness rafts 200 described herein. Such an electrical
harness raft 200 may be connected to the fan casing rafts 200D,
200B and the core casing rafts 200E, 200F using flexible cables
266, 267, 268, 269.
Connection between rafts 200A, 200B, 200C, 200D mounted on the fan
casing 24 to the rafts 200E, 200F mounted on the core casing 28 may
be provided at least in part by means other than an additional
electrical harness raft, for example using wire conductors with
insulating sleeves.
FIG. 13 also illustrates a direct connection 280A, 280B between two
electrical harness rafts 200C, 200D. The direct connection may be
between a connector or socket 280A provided with one raft 200C, and
a complimentary connector or socket 280B provided with another raft
200D. The connectors 280A, 280B may be provided in any suitable
manner, for example they may be embedded in the respective raft
200. Using direct connection between the rafts may avoid the need
for flexible connecting cables 261-269 where they are not required.
Thus, for example, an engine installation 10 may have some rafts
200A, 200B connected using a flexible cable 261, and other rafts
200C, 200D directly connected together.
FIG. 14 is a schematic cross-section through a gas turbine engine
10 in a plane normal to the engine axis X-X. FIG. 14 is a similar
view to FIGS. 12 and 13. The description of corresponding features
described above in relation to FIGS. 12 and 13 applies equally to
the FIG. 14 example, and will not be repeated in relation to FIG.
14.
In FIG. 14, an electrical harness raft 200C is electrically
connected to an ECU 325 (which may be an EEC or an EMU, for
example), using a flexible cable 326. It will be appreciated that
in other embodiments, the ECU 325 may be substituted for any other
component that comprises electrical conductors. The ECU 325 is
electrically connected to electrical conductors in the splitter 340
via a flexible cable 327. The electrical conductors in the splitter
340 may be in the form of a splitter electrical harness raft 345,
described in greater detail below in relation to FIGS. 15 and
16.
In the FIG. 14 embodiment, no two electrical harness rafts are
connected together via only a flexible cable. However, this need
not be the case, for example a flexible cable could be used to
connect the two rafts 200A and 200B, if required.
As mentioned above, a flexible cable 327 is used to connect the ECU
325 to the electrical conductors in the splitter 340. However,
alternative embodiments may have a direct (i.e.
connector-to-connector) connection between the ECU 325 and the
electrical conductors in the splitter 340. Such a direct connection
may be similar to the direct connection between the electrical
harness raft 200B and the splitter electrical harness raft 345 (see
FIG. 16), in which a connector 335A embedded in the electrical
harness raft 200B is directly connected to a connector 335B
embedded in the splitter electrical harness raft 345.
The ECU 325 may be mounted to the rest of the gas turbine engine in
any suitable manner. For example, in FIG. 14, the ECU 325 is shown
as being directly connected to the fan casing 24 (for example via a
mount, such as an AV mount). Other mounting methods could be used.
For example, the ECU 325 could be mechanically mounted on a raft,
which may be similar to the electrical harness rafts 200 other than
in that it may not necessarily comprise electrical conductors. Such
a mounting raft could be used to mechanically mount other
systems/components (such as any components/systems described herein
that could be mounted on an electrical harness raft including, by
way of example only, fluid pipes) of the gas turbine engine, and
may be provided anywhere on the gas turbine engine, as
required.
The splitter 340 is shown in greater detail in FIGS. 15 and 16. The
splitter 340 shown in FIGS. 15 and 16 may be enclosed within a
further splitter assembly, which may be referred to as a
bifurcation splitter (not shown), which may be aerodynamically
optimized. The further splitter assembly may comprise the external
surfaces that are gas-washed by the bypass flow. Alternatively, the
surfaces 341, 342 may form part of the external (gas-washed)
surfaces of the splitter assembly. In that case, there would
typically be an additional splitter fairing in the downstream
direction, for example to enclose components, such as cables 347,
348 that are attached to the splitter electrical harness raft 345.
However, such a bifurcation could be significantly smaller than a
conventional bifurcation because much (or all) of the bulky
electrical harness raft is no longer required, because the
electrical conductors are contained in the much more compact raft
345. Furthermore, other components/systems may be more effectively
packaged by mounting them on the raft 34. Thus, because the
bifurcation can be made much smaller, its adverse aerodynamic
impact may be reduced, and thus engine efficiency may be improved.
In the FIGS. 15 and 16 example, the leading edge of the splitter
340 is the line 343 of the wedge shape, but other shapes could
alternatively be used.
The splitter electrical harness raft 345 shown in FIGS. 15 and 16
has electrical conductors 345A embedded therein, which may take any
suitable form, such as electrical wires and/or flexible printed
circuits, as described herein in relation to the embedded
electrical conductors 210. In general, features of the electrical
harness rafts 200 described elsewhere herein may apply to the
splitter electrical harness raft 345. The splitter electrical
harness raft 345 may be connected (for example electrically
connected) to any other components, for example as explained above
in relation to FIG. 14. For example, connectors may be provided at
radially inner and/or radially outer ends of the splitter
electrical harness raft. Such connectors may be connected to other
components directly or via flexible cables, as explained herein. In
the FIG. 15 example, a flexible printed circuit 346B and a
conventional flexible wire 346A are shown extending from a radial
end of the splitter electrical harness raft 345. Further cables
347, 348 are also shown extending from the splitter electrical
harness raft 345, for connection to other components. Such cables
may be connected to the splitter electrical harness raft 345 using
a complimentary connector connected to a connector 349, which may
be embedded in the raft 345.
The splitter electrical harness raft 345 may have any other
component/system, or part(s) thereof, mounted thereon. In this
regard, the description provided elsewhere herein in relation to
components/systems that may be mounted on electrical harness rafts
200, and the techniques/apparatus for mounting such
components/systems, applies to the splitter electrical harness raft
345. By way of example only, in the FIG. 16 example, a fluid pipe
350 is shown as being mounted onto the raft 345 via a bracket
352.
Similarly, the techniques/apparatus for mounting the electrical
harness rafts 200 to the rest of the gas turbine engine
installation 10 described elsewhere herein may also apply to the
splitter electrical harness raft 345. For example, the splitter
electrical harness raft 345 may be mounted on anti-vibration (AV)
mounts.
Optionally, and as shown in the FIG. 16 example, the space 360
between the splitter electrical harness raft 345 and the splitter
340 may be filled, for example using a foam, such as: polyethylene
foam or polyurethane foam, reticulated foam, open cell foam,
Plastazote.RTM. (from Zotefoams.RTM.), high density closed cell
polyethylene foam, visco elastic memory foam, flame retardant foam.
Such foam may provide protection to the splitter electrical harness
raft 345, for example from vibration, and/or fire protection.
Optionally, the splitter 340 that contains an electrical harness
raft may act as (or may be) a firewall. For example, a fireproof
coating and/or material may be provided around at least a part of
the boundary of the splitter 340, for example at the inner and/or
outer radial end surfaces. Referring to FIG. 15, the outer radial
surface 361 may be fireproofed in this way. Accordingly, the
splitter 340 may form at least a part of a fireproof boundary
between an engine core fire zone and a fan case fire zone. The
engine core fire zone may be between the engine core casing 28 and
the engine core fairing 26. The fan case fire zone may be between
the fan casing 24 and the nacelle. It may be necessary and/or
desirable to isolate the fan case fire zone from the engine core
fire zone so as to prevent fire crossing therebetween.
Conventionally, a firewall may extend across a conventional
bifurcation and splitter assembly. Using the splitter 340 according
to the invention as at least a part of a fire boundary may reduce
the size (and thus weight) of the required additional firewall
through the bifurcation and/or substantially eliminate the need for
a separate firewall.
The splitter assembly, including the splitter electrical harness
raft 345, may contain any or all of the components/systems that
would usually pass through a conventional splitter. However, by
using a raft harness, the size and weight may be reduced.
Additionally or alternatively, the whole splitter assembly may
become a "cassette" that can more readily be disconnected, removed,
and/or replaced, for example during maintenance.
Where reference is made herein to a gas turbine engine
installation, it will be appreciated that this term may include a
gas turbine engine and optionally any peripheral components to
which the gas turbine engine may be connected to or interact with
and/or any connections/interfaces with surrounding components,
which may include, for example, an airframe and/or components
thereof. Such connections with an airframe, which are encompassed
by the term `gas turbine engine installation` as used herein
include, but are not limited to, pylons and mountings and their
respective connections. The gas turbine engine itself may be any
type of gas turbine engine, including, but not limited to, a
turbofan (bypass) gas turbine engine, turbojet, turboprop, ramjet,
scramjet or open rotor gas turbine engine, and for any application,
for example aircraft, industrial, and marine application.
It will be appreciated that many alternative configurations and/or
arrangements of electrical harness rafts 200 and gas turbine
engines comprising electrical harness rafts 200 other than those
described herein may fall within the scope of the invention. For
example, alternative arrangements of electrical harness rafts 200
(for example in terms of construction, layout and/or shape of
conductors 210 and/or rigid material 220 and/or the resulting raft
200) may fall within the scope of the invention and may be readily
apparent to the skilled person from the disclosure provided herein.
Alternative arrangements of connections between the rafts 200 and
between the rafts 200 other components may fall within the scope of
the invention and may be readily apparent to the skilled person
from the disclosure provided herein. Furthermore, any feature
described and/or claimed herein may be combined with any other
compatible feature described in relation to the same or another
embodiment.
* * * * *